Log barker

ABSTRACT

An annular barking rotor has a hub portion rotatably supported by a concentric anti-friction bearing and supports a plurality of radially pivotable barking arms each biased by an air motor mounted on the rotor and connected to an annular air chamber within the rotor. Air is supplied to the chamber and motors through a set of sliding air shoes, and the pressure of the air is controlled by a series of pilot operated valves, relay exhaust valves and regulating valves actuated by controls located at a remote console. Pilot operated diaphragm exhaust valves are carried by the rotor for connecting the air chamber directly to atmosphere and are actuated by a pulse of pilot air supplied through another air shoe connected to the main air supply through a pilot operated valve controlled by a valve also located at the console.

United States Patent Bentley et al.

[ LOG BARKER [7 21 Inventors: Allan M. Bentley; Elmer Christensen, bothof Everett, Wash.

[73] Assignee: The Black Clawson Company,

Middletown, Ohio [22] Filed: Sept. 2, 1970 [21] Appl. No.: 69,038

[52] [1.8. Cl ..144/208 E [5 1] Int. Cl ..B27l 1/00 [58] Field of Search..l44/208 E, 208, 208 AU [56] References Cited UNITED STATES PATENTS2,888,966 6/1959 Morgan et a1. ..l44/208 E 3,053,294 9/1962 Andersson144/208 E 3,137,329 6/1964 Smith ..144/208 E 3,236,273 2/1966 Rich etal. ..l44/208 E [15] 3,667,517 1 June 6,1972

Primary Examiner-D0nald R. Schran Attorney-Marechal, Biebel, French &Bugg [S7] 7 ABSTRACT An annular barking rotor has a hub portionrotatably supported by a concentric anti-friction bearing and supports aplurality of radially pivotable barking arms each biased by an air motormounted on the rotor and connected to an annular air chamber within therotor. Air is supplied to the chamber and motors through a set ofsliding air shoes, and the pressure of the air is controlled by a seriesof pilot operated valves, relay exhaust valves and regulating valvesactuated by controls located at a remote console. Pilot operateddiaphragm exhaust valves are carried by the rotor for connecting the airchamber directly to atmosphere and are actuated by a pulse of pilot airsupplied through another air shoe connected to the main air supplythrough a pilot operated valve controlled by a valve also located at theconsole.

13 Claims, 7 Drawing Figures PATENTEUJUH 6 I972 SHEET 10F 2 IN l/E/VTORS ALLAN M. BENTLEY 8 ELMER CHRISTENSEN A TTORNEYS PATENTEUJUN 6 19723.667. 517

SHEET 2 OF 2 FIG 5 9 -;9 7 99 45 A 96 FA. 97 5817c Ii" LOG BARKERBACKGROUND OF THE INVENTION In a log barker as disclosed in U.S. Pat.No. 3,361,168 which issued to the assignee of the present invention, itis desirable to provide for controlling from a remote console anincrease or a decrease in the pressure exerted by the barking arms onthe surface of a log being fed through the annular rotor. It is alsodesirable for the barker to incorporate means for quickly releasing thepressure exerted by the barker arms in the event the barker arms jam orreceive a larger diameter succeeding log. In the above patent, thepressure exerted by the barking arms is released by stopping thecontinuous air flow to the rotor through the sliding air shoes so thatthe air control system within the rotor exhausts and the pressureexerted by the barking arms releases.

7 Since a dwell 'or short time period is required to bleed the aircontrol system within the rotor for actuating the exhaust valves, therelease of the barking arms is not immediately responsive to theactuation of the remote control. Furthermore, the air control systemwithin the rotor for operating the barking arms, requires a continuoussupply of air. This requires that the air shoes must be in slidingpressure contact continuously during the debarking of a log and until itis desired to release the pressure exerted on the log by the barkmgarms.

SUMMARY OF THE INVENTION The present invention is directed to a logbarker which incorporates an improved rotor structure and control systemwhich provides for immediately releasing from a remote control consolethe pressure exerted on a log by the barking arms and for quicklyregulating the pressure exerted by the arms during a debarkingoperation. In accordance with a preferred embodiment of the invention,the rotor is supported by a large diameter anti-friction bearing whichis concentric with the rotor and has an inner race mounted on acylindrical hub portion of the rotor and an outer race secured to themain support frame.

The rotor carries a plurality of pivotal barking arms each operated byan air spring connected to an annular air reservoir chamber within therotor. Air is supplied to the rotor chamber through a set of air shoesslidably engaging a radial face on the rotor and connected to a main airsupply through pilot operated control valves, relay exhaust valves and amanually adjustable regulating valve. The rotor air chamber may beopened directly to atmosphere through a pair of large diaphragm actuatedexhaust valves which are pilot operated in response to an air pulsesupplied to the rotor through a sliding air shoe connected to a quickexhaust control valve located at the remote console.

More specific features and advantages of the invention wil be apparentfrom the following description, the accompanying drawings and theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a somewhat schematicelevational view of a log barker rotor constructed in accordance withthe invention;

FIG. 2 is a fragmentary section taken generally on the line 2-2 of FIG.1;

FIG. 3 is a fragmentary section taken on the line 33 of FIG 1;

FIG. 4 is a fragmentary section through the structure by which air issupplied to and removed from the rotor;

FIG. 5 is a section similar to FIG. 2 and taken generally on the line5-5 of FIG. 1;

FIG. 6 is a fragmentary section similar to FIG. 4 and showing an airtransfer shoe for supplying air to the rotor; and

FIG. 7 is a schematic diagram showing the pneumatic control system foroperating the rotor barking arms shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a rotor assemblyincluding a cast metal annular housing 16 having circurnferentiallyextending outer grooves 17 for receiving a multiple V-belt which isdriven by a variable speed motor (not shown). The housing 16 includes aninner cylindrical hub portion 19 (FIG. 2) which defines a cylindricalopening or passage 20 through which a log L is fed in a conventionalmanner. A large diameter anti-friction bearing 22 is positionedconcentric with the annular housing 16 and has an inner race 23 which ismounted on the cylindrical hub portion 19 of the housing 16 and issecured by a set of circumferentially spaced screws 24. The outer race26 of the bearing 22 is retained within a counterbore 27 of the mainsupport frame 30 by another set of screws 24.

A set of five arcuately shaped barking or abrading arms are eachpivotally supported by a pair of anti-friction bearings 36 (FIG. 3)mounted on a corresponding stub shaft 38 which projects axially from thehousing 16. An abrading tool 40 is mounted on the inner tip of each arm35 and is adapted to scrape bark from the log L when the rotor 15 isrotated in a clockwise direction as indicated in FIG. '1, this generalarrangement and operation being essentially as described in U.S. Pat.No. 3,361,168.

The operating pressure of each of the abrading arms 35 is determined bya corresponding air motor 42 which preferably consists of an air springor a rolling diaphragm air cylinder as shown in the above patent. Eachof the air motors 42 includes a trunnion 43 which is pivotally mountedon a pin shaft 44 (FIGS. 1 and 2) projecting axially into a bore formedwithin the rotor housing 16. Each of the pin shafts 44 has an L- shapedinner passage 46' which connects a port 47 within the corresponding airmotor support trunnion 43 with a passage 48 extending axially from anannular air reservoir or chamber 50, formed within the rotor housing16'and covered by a flat annular plate 52 secured to the housing. Theinner end of each air motor 42 is connected by a rod 54 (FIG. 1) to apivot pin 56 which extends through the corresponding barking am 35. Fromthe above, it is apparent that the air pressure in the air chamber andin the air motors 42 increases from a minimum to a maximum as thebarking arms 35 move between corresponding inner positions (FIG. I) foraccommodating the minimum diameter log L and outwardly retractedpositions (not illustrated) for accommodating the maximum diameter log.

By comparing FIGS. 2 and 5, it is apparent that the annular air chamber50 within the rotor housing 16 changes in axial depth at angularlyspaced intervals around the housing. That is, the rotor housing 16 isprovided with a recess 57 (FIG. 2) for each of the air motors 42, andthe air chamber 50 has its minimum axial depth in the area of eachrecess. Between the recesses 57, the air chamber 50 has its maximumaxial depth, and in each of these areas, the chamber 50 is connected bya radially extending passage 58 (FIG. 5) to another annular air chamber60 which is concentric with the chamber 50. As shown in FIGS. 2 and 5,the annular air chamber 60 also changes in axial depth at angularintervals around the rotor housing 16 to prevent interrupting therecesses 57 which receive the air motors 42. The air chamber 60 iscovered by an annular flat air transfer plate 62 which is secured to themotor housing 16 by a set of angularly spaced screws 63 and is sealed tothe rotor housing by a set of concentric O-rings 64.

Referring to FIG. 4, the air transfer plate 62 has a series of ten portsor holes 66 which are spaced uniformly around the plate. A tubular valveseat 67 is inserted into each of the holes 66 and is normally engaged bya spring biased plunger 68 of a corresponding poppet valve 70 which isrecessed within an axially extending counterbore 71 formed within therotor housing 16 opposite the annular air chamber 60. Each of the poppetvalves 70 includes a diaphragm 72 which is open on the left side (FIG.4) to atmosphere and open on the right side to the pressure within thechamber 60 through a port 73. The air transfer plate 62 also has aseries of two ports or holes 74 (FIG. 5 which are located approximatelydiametrically opposite on the plate 62 and are positioned radiallyoutwardly of the holes 66. Each of the holes 74 connects with acorresponding passage 76 formed within the rotor housing 16 andextending axially from the inner end of a counterbore 77. Each passage76 is normally closed by a spring biased washer 78 of a check valve 80which is threaded into the counterbore 77.

Each of the two counterbores 77 and the corresponding check valve 80 isopen to atmosphere through an outwardly extending passage 81 (FIG. 5)and a port 81a. The outer end of each passage 81 connects with acorresponding radially extending air chamber 82 defined within thechamber 50 between an inner plate 83 and an outer plate 84 which arewelded to the rotor housing 16. A counterbore 86 is formed within eachof the inner plates 83 concentric with a port 87 which opens into theouter end of the corresponding radially extending chamber 82. Acylindrical bore 89 is formed within the housing 16 in axial alignmentwith each of the counterbores 86, and a quick exhaust valve 90 ispositioned within each set of aligned bores 86 and 89.

Each of the exhaust valves 90 includes a body 92 (FIG. 5) which supportsa valve member 94 for sliding axial movement. Each of the valve members94 has a head 96 which normally seats on a circular lip 97 formed on theouter end of the housing 92. A curved exhaust duct 98 is secured to theouter end of each of the valve housings 92, and a plurality ofcircumferentially spaced ports 99 are formed within the valve housing 92to provide for exhausting the air reservoir chamber 50 through the ducts98 when the valve members 94 are open. The inner end of each valvemember 94 is connected to a flexible diaphragm 101 having its peripherysecured to the housing 92 by a clamping ring 102 which seats within thecorresponding counterbore 86.

A port 104 (FIG. 5) is formed within each of the inner plates 83 andreceives a corresponding tubular valve seat 106 through which thecorresponding air chamber 82 can communicate with the air reservoirchamber 50. A threaded bore 108 is formed within the rotor housing 16 inalignment with each of the ports 104, and a spring loaded diaphragmoperated poppet valve 110 is threaded into each of the bores 108 in amanner similar to the poppet valves 70 shown in FIG. 4. Each of thepoppet valves 110 includes a disk-like closure 112 which is normallyurged against the corresponding valve seat 106 to seal each of the airchambers 82 from the main annular reservoir chamber 50.

Referring to FIGS. 4 and 6, a pair of arcuate air transfer shoes 115 arepositioned adjacent the air transfer plate 62 in alignment with theannular array of holes 66 and poppet valves 70, and each shoe 1 issecured to a corresponding arcuate support housing 116 by a set ofscrews 117. Each air shoe 1 15 defines an arcuate cavity 118 whichconnects with a centrally located passage 119 formed within the housing116. Each of the air transfer shoes 1 15 and its corresponding housing116 is supported by a resilient diaphragm 120 which is secured to themain frame by an arcuately shaped plate 122. An air passage 123 isformed within each of the plates 122 and opens into a chamber 124 behindthe corresponding diaphragm 120. When the diaphragm is pressurized withair supplied through the passage 123, the corresponding air transfershoe 1 15 moves from its retracted position (FIG. 6) to an extendedposition slidably engaging the annular air transfer plate 62. As shownin FIG. 5, another air transfer shoe 115 is positioned in alignment withthe path of the holes 74 within the plate 62.

The pressure exerted by the air motors 42 on the barking arms iscontrolled or regulated from a remotely located or spaced controlconsole 130 (FIG. 7) generally in a manner as shown in the above patent.Air is supplied to the control console 130 through a line 132 which isconnected to an air supply tank 134 through a pressure regulator 136 anda filter 137. Air is supplied from the line 132 to a master controlvalve 140 having an operating solenoid 141 which may be actuated eithermanually or by a device 142 which senses the absence of a log from thebarker rotor 15. Pilot air is supplied from the valve through a line 143to the pilot actuators of a pair of pilot operated valves 145 and alsoto the pilot control of a pilot operated valve 146.

An air supply line 148 extends from the main supply line 132 to asolenoid actuated valve 150, and a lever actuated pressure regulatingvalve 152 is positioned in the line 148 for controlling the air pressuresupplied through the valve to a pair of relay exhaust valves 155 and tothe pilot operated valves 145. A flexible line 158 connects each of thevalves 145 to the passage 119 within the corresponding air shoe 1 15.Regulated pressure within the line 148 is also supplied to control arelay valve 160 positioned within a line 162 which connects the main airsupply line 132 to the pilot operated valve 146.

A line 164 connects the valve 146 to the chamber 124 in back of thesupport diaphragm 120 for each of the air transfer shoes 115. Thesolenoid actuated valve 150 is also connected directly to the main airsupply line 132 by a line 166, and a line 168 supplies air from the line132 to a manually actuated quick exhaust valve 170. A line 172 extendsfrom the valve 170 to the pilot control of a pilot actuated valve 175.The line 172 also supplies air through a pressure regulator 177 to thepassage 123 behind the diaphragm which supports the air transfor shoe115 aligned with the ports 74 within the air transfer plate 62. A line178 extends from the main air supply tank 134 through a pressureregulator 136 and a filter 137 to the relay exhaust valves 155 and tothe pilot operated valve 175. A line 179 extends from the valve to thepassage 119 for supplying air through the corresponding air transfershoe 1 15 to the ports or holes 74 within the air transfer plate 62.

In operation, the lever actuated pressure control valve 152 is adjustedat the control console 130 according to the pressure desired within airmotors 42, as for example, 40 psi. The master control valve 140 isactuated so that valves 145 open and lines 158 are pressurized to theselected pressure. When the lines 158 are pressurized, air is suppliedthrough the corresponding air transfer shoes 115 and into the rotorchambers 50 and 60 until the air pressure within the chambers and withineach of the air motors 42 arrives at the preselected pressure. As therotor 15 is driven, and the holes 66 rotate past the adjacent airtransfer shoes 115, the poppet valves 70 assure that the selectedpressurized air is retained in the chambers 50 and 60 and the air motors42.

Preferably, the chambers 50 and 60 and the air motors 42 are pressurizedto the selected pressure when no log is in the rotor and the barkingarmsare therefore in their innermost positions. For example, the device 142may be a microswitch operated by one of the arms 35 in its innermostposition, or it may represent a switch responsive to a laser beamsensing the absence of a log from the rotor. As a log is fed into therotor, the device 142 is caused to actuate the solenoid 141 to close themaster control valve 140. This causes the pilot operated valves 145 and146 to close, and the lines 158 and 164 exhaust so that thecorresponding air transfer shoes 115 are released from the rotor plate62.

If it is desired to increase momentarily the air pressure within the airmotors 42 during a barking operation to provide a corresponding increasein the pressure exerted by the barking arms 35 on a log L as it is beingfed through the rotor 15, the solenoid valves 140 and 150 are manuallyactuated so that the higher air pressure within the line 132 is suppliedto the lines 158 through the bypass line 166. The buildup of airpressure within the rotor chambers 50 and 60 and the air motors 42 willcontinue as long as the solenoid valves are energized. When the solenoidvalve 150 is deenergized, the air pressure within the rotor chambers 50and 60, the air motors 42 and in the lines 158 will reduce to the normaloperating pressure as selected by the regulating valve 152. That is,when the pressure in the lines 158 and in the rotor air chambers 50 and60 exceeds the pressure in the line 148, air flows outwardly from therotor chambers, backward through the lines 158 and exhausts through therelay exhaust valves 155.

in the event it is desired to release immediately the air pressurewithin the air motors 42 and the corresponding pressure exerted by thebarking arms '35, as for example, to avoid jamming the rotor, the valve170 at the control console 130 is actuated thereby pressurizing the line172 to actuate the pilot valve 175 and to pressurize the correspondingdiaphragm 120 to urge the corresponding air transfer shoe 115 intoengagement with the air transfer plate 162. When the valve 175 isactuated, pressurized air within the line 176 flows through the line179, the connected air transfer shoe 1 15, the holes 74 and through thepassages 76 and 81 to the two air chambers 82 within the rotor housing16.

The first puff of pressurized air within the rotor chambers 82 iseffective to open the corresponding poppet valves 1 so that the chambers82 are opened to the air pressure within the rotor chambers 50 and 60.When the chambers 82 are so pres surized, the diaphragm actuated exhaustvalves 90 open thereby providing for immediate release or exhaust of thepressurized air within the rotor chambers 50 and 60 and within the airmotors 42 connected to the chambers. When the control valve 170 isreleased, the pilot operated valve 175 closes, and the pressure urgingthe corresponding air transfer shoe 115 against the air transfer plate62, is released. When the pilot operated valve 175 closes, thepressurized air within the rotor chambers 82 and the passages 81 exhaustthrough the exhaust passages or ports 81a. If the selected air pressurein the air motors 42 and in the rotor chambers 50 and 60 is satisfactoryfor performing a barking operation on a particular log, the pressureexerted by the air transfer shoes 115 against the air transfer plate 62on the rotor may be released to minimize wear on the shoes and plate.This is accomplished simply by actuating the master control valve 140 toexhaust the air within the line for actuating the pilot operated valves145 and 146. When the valve 146 closes, the air in the line 164 isexhausted through the valve 146.

From the drawings and the above description, it is apparent that abarking rotor and a control system constructed in accordance with thepresent invention, provides desirable features and advantages. Forexample, during the debarking of a log, the master control valve 140 isnormally closed, and the air transfer shoes 115 are released from theair transfer plate 62. After the log is debarked and before the next logis fed into the rotor, and therefore whenthe arms 35 are innermost andthe total volume of cylinders 42 is at a maximum, the devices142automatically actuates the solenoid 141 to open the valve 140 so thatthe air pressure within the rotor chambers 50 and 60 is readjusted, ifnecessary, to the pressure set by the regulating valve 152.

During a debarking operation, the pressure exerted by the barking arms35 may be changed as desired by adjusting the lever actuated valve 152and manually actuating the solenoid 141 to open the valve 140. When theair pressure in the lines 158 is less than the air pressure within therotor chambers 50 and 60, the poppet valves 70 function to permit theair in the air motors 42 and rotor chambers 50 and 60 to flow out of therotor through the lines 158 and be exhausted through the relay exhaustvalves 155. That is, since the pressurized air within the rotor chamber60 acts against both the diaphragm 72 and the valve member 60 of eachpoppet valve 70, the force which normally holds each valve member 68against its corresponding seat 67, is equal to the air pressure withinthe chamber 60 multiplied by the difference in area between the valvemember 68 and the valve seat 67. This force is relatively light so thatonly a relatively low pressure is required in the lines 158 to open thepoppet valves 70 and thereby to permit the pressure in the rotorchambers 50 and 60 to balance with the pressure in the lines 158. Inaddition, an increase in the pressure ex erted by the barking arms maybe quickly accomplished by actuating the valve 150 so that the lines 158are supplied with air directly from the main air supply line 132,bypassing the pressure regulator valve 152. If it is desired to maintainthe increased pressure exerted by the barking arms, the regulating valve152 is correspondingly adjusted.

Another important feature of the invention is provided by the quickexhaust control system. That is, simply by actuating the valve 170 atthe main control console 130, a puff of air is introduced into the rotorchambers 82 thereby opening the poppet valves 110 which are balanced inthe same manner as the valves 70. This pemiits the pressurized air inthe rotor chamber 50 to actuate the large diaphragm operated exhaustvalves 90 so that the air is immediately released or exhausted from therotor chambers 50 and 60. As a result, the release of the pressurizedair within the air motors 42 is immediately responsive to actuation ofthe control valve 170. This quick exhaust feature is especiallydesirable in that it enables the operator to prevent jamming of thebarking anns, for example, by an irregular projection on a log.

As mentioned above, the control system of the invention also providesfor releasing the pressure engagement of the air transfer shoes 1 15against the air transfer plate62 on the rotor 15 without releasing thepressurized air within the rotor chambers 50 and 60 and within the airmotors 42. This feature is desirable during a barking operation to wearon the air transfer shoes 1 15 and the plate 62 when it is not necessaryto adjust the selected air pressure in the rotor chambers 50 and 60.Another feature of the invention is provided by the support of the rotor15 by the large diameter antifriction bearing 22. This supportarrangement for the rotor 15 enables the rotor to withstand substantialimpact loading or forces and significantly increases the service life ofthe rotor in comparison with the conventional support system including aplurality of rollers spaced around the periphery of the rotor.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. An improved log barker for scraping bark from logs of various sizesand shapes, comprising a frame, an annular rotor adapted to receive alog therethrough, means mounted on said frame and supporting said rotorfor rotation, a plurality of barker arms pivotally mounted on said rotorfor generally radial movement, a corresponding plurality of air motorsmounted on said rotor and connected to bias said arms inwardly, wallmeans defining a circumferentially extending air chamber within saidrotor and connected to saidair motors, means for supplying pressurizedair from a remote air source to said chamber while said rotor isrotating, remotely operable control means for regulating the pressure ofair in said chamber and in said air motors while said rotor is rotating,exhaust valve means connected to said wall means defining said chamberand having a port efi'ective to open said chamber directly toatmosphere, and remotely operable control means for opening said exhaustvalve means to effect immediate release of pressurized air from saidchamber and said air motors through said port.

2. A log barker as defined in claim 1 wherein said exhaust valve meanscomprise at least one diaphragm actuated exhaust valve, means defining apassage connecting said air chamber to said diaphragm valve, poppetvalve means within said passage, and remotely operable control means foractuating said poppet valve means causing the pressurized air withinsaid chamber to open said exhaust valve in response to opening of saidpoppet valve means.

3. A log barker as defined in claim 1 wherein said means for supplyingair to said rotor chamber include at least one air transfer shoeslidably engaging said rotor, air actuated means for moving said shoebetween a retracted position and an extended position engaging saidrotor, an air supply line connected to said shoe, a pilot operatedcontrol valve in said supply line, and means for simultaneouslysupplying air to said air actuated means and said pilot operated valve.

4. A log barker as defined in claim 1 wherein said means for supplyingair to said rotor chamber includes at least one air transfer shoe, airactuated means for moving said shoe between a retracted position and anextended position engaging said rotor, and rotor, and valve means forretaining air at a selected pressure within said rotor when said airshoe is moved to said retracted position.

5. A log barker as defined in claim 1 wherein said means supporting saidrotor for rotation comprises an annular bearing having an axis common tosaid rotor and positioned to receive the log therethrough.

6. A log barker as defined in claim 5 wherein said rotor includes aninner generally cylindrical hub portion, and an antifriction saidbearing having an inner race mounted on said hub portion and an outerrace secured to said frame.

7. A log barker as defined in claim 1 wherein said means for supplyingair to said rotor chamber include at least one air transfer shoe, andair actuated diaphragm means supporting said shoe for movement between aretracted position and an extended position engaging said shoe.

8. An improved log barker for scraping bark from logs of various sizesand shapes, comprising a frame, an annular rotor adapted to receive alog therethrough, means mounted on said frame and supporting said rotorfor rotation, a plurality of barker arms pivotally mounted on said rotorfor generally radial movement, a corresponding plurality of air motorsmounted on said rotor and connected to bias said arms inwardly, meansdefining an air chamber within said rotor and connected to said airmotors, means for supplying pressurized air from a remote air source tosaid chamber while said rotor is rotating, remotely operable controlmeans for regulating the pressure of air in said chamber and in said airmotors while said rotor is rotating, said rotor including an innergenerally cylindrical hub portion, and said supporting means includingan anti-friction bearing having an inner race mounted on said hubportion and an outer race secured to said frame.

haust valve means in response to an air pulse supplied to said exhaustvalve means.

10. An improved log barker for scraping bark from logs of various sizesand shapes, comprising a frame, an annular rotor adapted to receive alog therethrough, means mounted on said frame and supporting said rotorfor rotation, a plurality of barker arms pivotally mounted on said rotorfor generally radial movement, a corresponding plurality of air motorsmounted on said rotor and connected to bias said arms inwardly, meansdefining an air chamber within said rotor and connected to said airmotors, means for conducting pressurized air to and from said chamberwhile said rotor is rotating and including a plurality of normallyclosed poppet valves mounted on said rotor to retain the air within saidchamber and said air motors, remotely operable control means forregulating the pressure of air in said conducting means and in saidchamber and air motors while said rotor is rotating, and said poppetvalves including means to cause opening of said valves in response toair pressure within said conducting means below the air pressure withinsaid rotor chamber to provide for reducing the air pressure within saidmotors in response to actuation of said control means.

11. A log barker as defined in claim 10 wherein each said poppet valveincludes a movable valve member connected to a diaphragm, and means fordirecting the air pressure within said chamber against said diaphragm tobalance part of the air pressure acting on said valve member.

12. A log barker as defined in claim 10 wherein said means forconducting air to and from said rotor chamber include at least one airtransfer shoe and air actuated means for moving said shoe between aretracted position and an extended position engaging said rotor, andsaid poppet valves are effective to retain a selected air pressurewithin said rotor when said air shoe is moved to said retractedposition.

13. A log barker as defined in claim 12 including control means forautomatically operating said air actuated means in response to theabsence of a log from said rotor to move said shoe to said extendedposition and to reset the selected air pressure within said chamber.

1. An improved log barker for scraping bark from logs of various sizesand shapes, comprising a frame, an annular rotor adapted to receive alog therethrough, means mounted on said frame and supporting said rotorfor rotation, a plurality of barker arms pivotally mounted on said rotorfor generally radial movement, a corresponding plurality of air motorsmounted on said rotor and connected to bias said arms inwardly, wallmeans defining a circumferentially extending air chamber within saidrotor and connected to said air motors, means for supplying pressurizedair from a remote air source to said chamber while said rotor isrotating, remotely operable control means for regulating the pressure ofair in said chamber and in said air motors while said rotor is rotating,exhaust valve means connected to said wall means defining said chamberand having a port effective to open said chamber directly to atmosphere,and remotely operable control means for opening said exhaust valve meansto effect immediate release of pressurized air from said chamber andsaid air motors through said port.
 2. A log barker as defined in claim 1wherein said exhaust valve means comprise at least one diaphragmactuated exhaust valve, means defining a passage connecting said airchamber to said diaphragm valve, poppet valve means within said passage,and remotely operable control means for actuating said poppet valvemeans causing the pressurized air within said chamber to open saidexhaust valve in response to opening of said poppet valve means.
 3. Alog barker as defined in claim 1 wherein said means for supplying air tosaid rotor chamber include at least one air transfer shoe slidablyengaging said rotor, air actuated means for moving said shoe between aretracted position and an extended position engaging said rotor, an airsupply line connected to said shoe, a pilot operated control valve insaid supply line, and means for simultaneously supplying air to said airactuated means and said pilot operated valve.
 4. A log barker as definedin claim 1 wherein said means for supplying air to said rotor chamberincludes at least one air transfer shoe, air actuated means for movingsaid shoe between a retracted position and an extended position engagingsaid rotor, and rotor, and valve means for retaining air at a selectedpressure within said rotor when said air shoe is moved to said retractedposition.
 5. A log barker as defined in claim 1 wherein said meanssupporting said rotor for rotation comprises an annular bearing havingan axis common to said rotor and positioned to receive the logtherethrough.
 6. A log barker as defined in claim 5 wherein said rotorincludes an inner generally cylindrical hub portion, and ananti-friction said bearing having an inner race mounted on said hubportion and an outer race secured to said frame.
 7. A log barker asdefined in claim 1 wherein said means for supplying air to said rotorchamber include at least one air transfer shoe, and air actuateddiaphragm means supporting said shoe for movement between a retractedposition and an extended position engaging said shoe.
 8. An improved logbarker for scraping bark from logs of various sizes and shapes,comprising a frame, an annular rotor adapted to receive a logtherethrough, means mounted on said frame and supporting said rotor forrotation, a plurality of barker arms pivotally mounted on said rotor forgenerally radial movement, a corresponding plurality of air motorsmounted on said rotor and connected to bias said arms inwardly, meansdefining an air chamber within said rotor and connected to said airmotors, means for supplying pressurized air from a remote air soUrce tosaid chamber while said rotor is rotating, remotely operable controlmeans for regulating the pressure of air in said chamber and in said airmotors while said rotor is rotating, said rotor including an innergenerally cylindrical hub portion, and said supporting means includingan anti-friction bearing having an inner race mounted on said hubportion and an outer race secured to said frame.
 9. A log barker asdefined in claim 8 including exhaust valve means connected to said airchamber and effective to exhaust air directly from said chamber and saidair motors, remotely operable control means for actuating said exhaustvalve means, and said control means being effective to open said exhaustvalve means in response to an air pulse supplied to said exhaust valvemeans.
 10. An improved log barker for scraping bark from logs of varioussizes and shapes, comprising a frame, an annular rotor adapted toreceive a log therethrough, means mounted on said frame and supportingsaid rotor for rotation, a plurality of barker arms pivotally mounted onsaid rotor for generally radial movement, a corresponding plurality ofair motors mounted on said rotor and connected to bias said armsinwardly, means defining an air chamber within said rotor and connectedto said air motors, means for conducting pressurized air to and fromsaid chamber while said rotor is rotating and including a plurality ofnormally closed poppet valves mounted on said rotor to retain the airwithin said chamber and said air motors, remotely operable control meansfor regulating the pressure of air in said conducting means and in saidchamber and air motors while said rotor is rotating, and said poppetvalves including means to cause opening of said valves in response toair pressure within said conducting means below the air pressure withinsaid rotor chamber to provide for reducing the air pressure within saidmotors in response to actuation of said control means.
 11. A log barkeras defined in claim 10 wherein each said poppet valve includes a movablevalve member connected to a diaphragm, and means for directing the airpressure within said chamber against said diaphragm to balance part ofthe air pressure acting on said valve member.
 12. A log barker asdefined in claim 10 wherein said means for conducting air to and fromsaid rotor chamber include at least one air transfer shoe and airactuated means for moving said shoe between a retracted position and anextended position engaging said rotor, and said poppet valves areeffective to retain a selected air pressure within said rotor when saidair shoe is moved to said retracted position.
 13. A log barker asdefined in claim 12 including control means for automatically operatingsaid air actuated means in response to the absence of a log from saidrotor to move said shoe to said extended position and to reset theselected air pressure within said chamber.